water temp.. how much is too much and how much is normal?

[1994Diesel]

I just climbed the rockies with my 94 250 with a 2300lb cab over camper + or - 500lb to 800lb of ppl and gear, and went over a few passes as high if not higher than 10,000ft elevation and I've been struggling with my wafer temp, I saw 250 at the highest, I never ever let it get this high, it scares the crap outa me , but on the long up hill pulls the wafer temp gets very high. Usually I've been seeing 220 to 240 on the long pulls, I jusf baby it in 2nd or 3rd. how high is way to high and what causes damage( I did a search, just couldn't find a straight answer)? I have not boiled over this frip. I know my fan clutch is good and I'm shure that my rad is not clogged because af idling, 190*f, I put my hand behind the fan and it feels Very hot, so there is heat exchange. My theory is that my t-stat isn't opening far enough to let enough coolant through on the long pulls, which could explain the overheating

For the serpentine belt type it isn't to bad of a job right? Easy enough to do in a parking lot? I've done some digging with fhe search and found that tstats arnt to expensive and that stant makes one now that is comparable to oe?




What do you guys think? Thanks

 

[hayisforhorses]

watching this one, was wandering on temps too

 

[rhkcommander]

does the heater core blow hot as hades? I dont think it would be the tstat malfunctioning unless the wrong ones slapped in there

Also is the fan shrouded with the plastic shroud or is it just fan and radiator and no BS in between. makes a difference

 

[subway]

i have heard you always want to get the thermostat from IH or Ford. other parts stores sell them but they are not the right temp.

at 250 i would be puckering up since the overtemp light is supposed to come on about 240. i dont like going over 230 myself, as far as what is the max temp you can run, just before something gives. but you are flirting with trouble at that temp

just because you are blowing hot air behind the radiator does not mean it is doing its job to the fullest. yes it is getting rid of heat but it might not be enough. i have run into this before on older radiators that need cleaned out or replaced.

something else to consider is where is your timing at, these motors wear to the retarded side when there are a few miles on the injection pump. this can cause your engine to run hotter and have less power.

 

[1994Diesel]

Thanks for the replies, as far as timing goes I'm not to shure, I don't see excessive egts nor do I lack poower on the grades, I could go up these passes a lot faster if I wasn't so worried about water temp.

The air is prerty damn hot when the water temp is at 190... I did just replace the coolant along with a flush.

The heater is blowing relativly hot air, I've been turning it on to help with the climbs, and I do have a fan shrowd

 

[franklin2]

Are you positive the fan clutch is working? Most people that have overheating problems while pulling do have a fan clutch problem, and the clutches do have a very high failure rate. I personally have never heard one that was working, but the few people who do have a working clutch fan say you can't mistake the noise when it kicks in.

 

[1994Diesel]

Yea I'm pretty shure its working, I can hear it kick in at 220 and drop of arond 210ish, maybe I should change it for peace of mind...

 

[franklin2]

Since you are throwing out temperatur numbers, I am assuming you have a aftermarket gauge? Where is it plugged into the engine? Do you still have your factory temp gauge hooked up also? Do you still have the over temp switch hooked up?

I know the couple of times I ran my engine hot, I could smell the oil that had leaked on the engine getting hot and cooking.

 

[1994Diesel]

I do have an aftermarket gauge, the probe is on theTt drivers side head. Thankfully I havnt smelled anything funny while its hot. The factory gauge is still "working", when I'm at the L I'm reading about 220ish

 

[The Warden]

FWIW the thermostat should be starting to open at 192 F and should be fully open by 210 F or so. I've never had a problem with overheating, but I would be stopping to let it cool off if it got above 230 F or so. The general consensus is that, if the overtemp light has come on (at 244 F), you're already risking damage to the engine.

Do you have a pyro? If so, what were your EGT's when the water temp was up to 250? With water temp that high, I tend to think that your EGT's would have been sky-high...the oil spraying the bottoms of the pistons would have gotten VERY hot and transferred that heat to the coolant via the oil cooler. Either that, or your thermostat's sticking or your fan clutch isn't engaging properly...in any event, 250 F is wayyyyyy too hot

 

[icanfixall]

Just reading this.... Seeing that you don't have the over temp sender in the head any longer there is no way the dash gauge will peg like its supposed to do if the coolant temp reaches 242 degrees. Thats all the large sender does in the drivers side head. It just pegs the dash gauge and the "check engine "lite comes on. The 250 degrees is about 15 or 20 degrees too hot. Back out of the throttle and don't let things get this hot. As for thermostats most here will only trust the factory thermostat. Some few members have been lucky using the after market stuff but your taking a big chance thats not really worth it. The factory stat strats to open at 192 and is fully open at 212 degrees just like posted. The alternater and mount needs to be removed to install the stat along with the fiel filter mount. Really not a bad job either. When you look at the new thermostat see the black rubber ring type gasket around the sliding part. It kinda bulges out and its there to create a positive shutoff when the stat is closed. They are a metal to metal seal and supposedly don't seal perfectly. Thats not true. I cut off that part but leave the bottom part that is welded to the body. It allows for better flow thru the stat. Never have I had any issues with over cooling thru a leaky thermostat. When you drain down the cooling system to change the thermostat look into the top rad tank for corrosion around the tubes. If you see some have the radiator cleaned out. If your still tunning the crushed factory down pipe change that. If you still have the stock exhaust with a muffler then get rid of it. Run a straight pipe without a muffler. All this exhaust work will cool down the motor too. Any psd exhaust from the down pipe back will fit your truck. You just need a replacement ats down pipe. A 4 inch exhaust pipe system from the 3 inch down pipe will be fine. A 5 inch is unecessary and a waiste of cash...

 

[1994Diesel]

Ok, well I hop I didn't do any damage to the engine, it wasn't up at 250 for too long, maybe a couple of seconds.

My egts were around 800 to 900, boost was no more than 7psi,

I'm at a loss, I guess im going to proceed with changing the t-stat. I know for a fact that the fan clutch works, I can hear it pretty well.

I read here on that the stant 385-190 t-stat is comparable to oe, I really hope so because I can get one now.

Gary, I have it straight piped but do need to ditch the stock down pipe.

 

[subway]

if you test the old thermostat with a pan of water and a candy thermometer it will let you know for sure one way or the other. i always test mine now, old and new, much easier in your home than the side of the road.

do you have a infrared thermometer to check the temperature drop across the radiator?

 

[The Warden]

if you test the old thermostat with a pan of water and a candy thermometer it will let you know for sure one way or the other. i always test mine now, old and new, much easier in your home than the side of the road.

+1 on what Jred said about testing the old AND the new thermostat. If your EGT's were that low and your water temp was that high, either the gauge is bad or you've got a cooling system issue...be it a thermostat or a radiator that's not working properly or whatever. Get the thermostat changed out and let's see how she does then

 

[1994Diesel]

ok, sounds good,

hey, is the paper gasket necessary for the thermostat housing, can i get away with using black permetex rtv?

I have no way of testing the thermostats now. I really hope i dont have any serious cooling issues.